Methods and Devices for Automated Biopsy and Collection of Soft Tissue

ABSTRACT

Instruments for performing percutaneous biopsy procedures are disclosed, which have advantageous features for improving functionality and performance over prior art devices. These instruments comprise two types, single-use devices, and multiple-use devices having active tissue capture capability. Improved features include the ability to retrieve and evaluate multiple tissue samples during a single insertion procedure, without physical handling of the samples, as well as constructional features, such as a molded tissue cassette housing, variant vacuum port embodiments suited for different tissue environments, and a method for backflushing the instrument to remove biological debris, among others.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of co-pending parentapplication Ser. No. 08/217,246, filed. Mar. 24, 1994.

FIELD OF THE INVENTION

The present invention relates to methods and devices for tissuesampling, and more specifically to improved biopsy instruments andmethods for acquiring subcutaneous biopsies and for removing lesions.

BACKGROUND OF THE INVENTION

It is often desirable and frequently necessary to sample or test aportion tissue from humans and other animals, particularly in thediagnosis and treatment of patients with cancerous tumors, pre-malignantconditions, and other diseases or disorders. Typically, in the case ofcancer, when the physician establishes by means of procedures such aspalpation, x-ray, or ultrasound imaging that suspicious circumstancesexist, a biopsy is performed to determine whether the cells arecancerous. Biopsy may be done by an open or percutaneous technique. Openbiopsy, which is an invasive surgical procedure using a scalpel andinvolving direct vision of the target area, removes the entire mass(excisional biopsy) or a part of the mass (incisional biopsy).Percutaneous biopsy, on the other hand, is usually done with aneedle-like instrument through a relatively small incision, blindly orwith the aid of an artificial imaging device, and may be either a fineneedle aspiration (FNA) or a core biopsy. In FNA biopsy, individualcells or clusters of cells are obtained for cytologic examination andmay be prepared such as in a Papanicolaou smear. In core biopsy, as theterm suggests, a core or fragment of tissue is obtained for histologicexamination which may be done via a frozen section or paraffin section.

The type of biopsy utilized depends in large part on circumstancespresent with respect to the patient, and no single procedure is idealfor all cases. However, core biopsy is extremely useful in a number ofconditions and is being used more frequently by the medical profession.

Two types of image guided percutaneous core breast biopsy instrumentsare presently available. One such instrument is a spring-poweredsingle-use device, such as the BIOPTY® gun, available from C.R Bard,Inc. Such a gun is shown and described in U.S. Pat. Nos. 4,699,154 and4,944,308, as well as in U.S. Reissued Pat. No. Re. 34,056, all of whichare herein expressly incorporated by reference These devices are usefulbecause of their inexpensive construction, enabling them to beeconomically used for only a single patient, and because they arelightweight and easy to use. However, they also have disadvantages. Animportant disadvantage is that the small core size makes it necessary toaccurately place the needle when sampling small lesions. To sample alesion thoroughly, many separate insertions must be made. Each time anew sample is taken, the device must be removed, and the breast or organmust be punctured again upon re-insertion of the device. This action istedious and time consuming.

A further disadvantage of such single-use guns is the needle typicallyused in such a device, e.g. the True Cut® needle manufactured byTravenol Laboratories. This needle optimally allows a roughlycylindrical shaped sample of tissue, termed a “core”, to be obtainedfrom a pointed, side cutting device, percutaneously, and comprises apointed inner stilette with a side-facing notch to receive tissue nearits distal pointed end and an outer, sharpened sliding cannula Inoperation, once the lesion is targeted, the inner stilette is thrustinto the organ or lesion of interest Tissue passively prolapses into theside facing notch and the outer cannula is rapidly advanced, therebysevering the sample of tissue contained within the notch. Unfortunately,the True Cut® needle is rough on organs and lesions, often onlyobtaining small fragments of tissue, and is quite operatordependent—some individuals are good at operating the device and some arenot. It also is tissue selective, meaning that the piercing stilette andsliding cutter can “push away” the lesion of interest, particularly insituations where a relatively large lesion is surrounded by much softertissue (i.e. fat).

The second type of image guided percutaneous core breast biopsyinstrument currently available is a vacuum-assisted automatic corebiopsy device. One such successful biopsy gun is shown and disclosed inrelated parent application Ser. No. 08/217,246, filed on Mar. 24, 1994,which is commonly owned by the assignee of the present application andis herein incorporated by reference. This gun has the capability toactive capture tissue prior to cutting the tissue. Active capture allowsfor sampling through non-homogeneous tissues, meaning that the device isequally capable of cutting through hard and soft tissue. The gun alsoincludes means to direct and position the cutting chamber in arbitrarypositions about and along its longitudinal axis, means for rapid andatraumatic removal of an arbitrary number of core samples with only asingle needle insertion into the body and organ, and means for codingand decoding the location from which the samples were obtained Together,these capabilities allow for more complete sampling of large lesions andfor the complete removal of small lesions. This type of instrument hasbeen very successful in permitting the obtainment of a plurality oftissue samples from different locations with only a single needleinsertion, as well as in obtaining high quality samples in a mannerwhich does not require direct handling of the samples by the operator.However, it does not operate equally well in all procedures and in allbodily environments. For example, instrument performance and successoften varies dependent upon the type of body tissue being sampled; i.e.relatively fatty or relatively hard.

What is needed then, are innovations for improving the quality andcompleteness of the tissue sample obtained using a single-use corebiopsy instrument, as well as constructional improvements and variantswith respect to the active capture type of instrument which will permitit to operate with maximum efficiency and to operate equally well in alltissue environments.

SUMMARY OF THE INVENTION

This invention addresses the aforementioned needs by providing a numberof important new features and innovations for the active capture type ofbiopsy instrument which each collectively or singly contribute toimproved and more versatile operation For example, such innovationsinclude a molded tissue cassette housing, permitting easy andinexpensive. fabrication while also permitting the handling and viewingof multiple tissue samples without physical contact by the instrumentoperator. The housing is interconnected with the piercing needle using athumbwheel which permits the needle to rotate relative to the housing,thereby preventing the vacuum tube from wrapping about the housing.Several variant vacuum port embodiments are disclosed, each of whichhave advantages in certain tissue environments. Also disclosed is amethod for backflushing biological debris from the instrument whichbuilds up after repeated sampling procedures, without removing theinstrument from the selected tissue location

With respect to the single-use type of biopsy instrument, several tissuecapture embodiments are disclosed for improving the capture process, sothat complete and well preserved samples are obtained. Many of theseembodiments are also applicable for use with the active captureinstrument type.

More particularly, in one aspect of the invention, a biopsy instrumentis provided which comprises a housing and a needle assembly, wherein theneedle assembly includes a tubular piercing member having a distalpointed end and a laterally positioned tissue receiving port proximateto the distal pointed end which opens into a tissue sample chamber. Thetubular piercing member is rotatably attached to the housing and held inan axially fixed position within a selected tissue mass. The needleassembly further includes a cannular cutting member adapted to coactwith the tubular piercing member to cut a tissue sample from the tissuemass. The tissue sample is transported to a proximate end of the tubularpiercing member by the cutting member as it is withdrawn proximallyalong the tubular piercing member. An elongate knock-out pin is disposedcoaxially within the tubular piercing member and the cannular cuttingmember for the primary purpose of dislodging the tissue sample from thecutting member at a predetermined location as the cutting member iswithdrawn.

Surprisingly, the inventors have found that preferably, in order tominimize tissue clogging of the cutter, the knock-out pin should have aneffective diameter or cross-sectional area of at least 0.030 inches, andthe ratio of the effective diameter of the knock-out pin to the internaldiameter of the cannular cutter should be at least approximatelyone-half.

In another aspect of the invention, a biopsy instrument includes anelongate hollow outer piercing needle having a lumen, a sharpened distalend for piercing tissue, and a lateral opening located proximal to thesharpened distal end for receiving a portion of a tissue mass positionedadjacent to the lateral opening, Also included are an elongate innercutting cannula having a lumen, which is disposed coaxially and slidablywithin the outer piercing needle. The inner cannular has a sharpeneddistal end for cutting the portion of tissue protruding into the lateralopening of the outer piercing needle when the inner cannula slidesdistally past the lateral opening. This causes the portion of cut tissueto be deposited within the inner cannula proximal to the distal end Avacuum generator generates a vacuum pressure which fluidly communicateswith the lateral opening through the inner cannula lumen. In such anembodiment, it is often desirable to prevent the tissue sample frommigrating proximally through the cutting cannula lumen, so an inventivetissue stop device is disposed in the lumen of the inner cannula whichhas a structure, preferably a corkscrew portion of a linear wire,disposed proximally of the lateral opening. This structure sufficientlyobstructs the lumen so that the tissue sample cannot migrate proximallypast it.

In yet another aspect of the invention, a biopsy instrument includes anouter hollow cannula having a distal end portion which comprises aplurality of leaftlets. Each leaflet has a proximal end which is hingedto the outer cannula wall and a distal end, and are each biased to pivotabout their hinges to a closed position wherein the distal ends of theleaflets contact one another. The instrument further includes an innerhollow cannula, and at least one of the inner and outer cannular isslidable relative to the other cannula, so that first the inner cannulamay be extended distally with respect to the outer cannula to force theleaflets to an open position, and to cut and contain a tissue sample,and then the outer cannula may be extended distally with respect to theinner cannula sufficiently so that the leaflets clear the inner cannulaand snap closed about their hinges, thereby severing the tissue sampleand containing it within the inner cannula.

In a further aspect of the invention, a biopsy instrument has an outerhollow cannula having a sharpened distal end portion and an inner hollowcannula having a distal portion which is biased to expand radially atits distal end. At least one of the cannulas is slidable relative to theother cannula, so that first the inner cannula may be extended distallywith respect to the outer cannula, such that the inner cannula distalportion expands radially to capture a tissue sample. Then the outercannula may be extended distally with respect to the inner cannulasufficiently so that the distal end portion of the inner cannula isforced by the outer cannula to close about and sever the tissue sample,thereby containing the sample within the inner cannula The distalportion of the inner cannula may comprise, for example, either analligator tip having a pair of hinged jaws which are biased to expandradially, or a plurality of hooked extractors.

Still another aspect of the invention involves a method for flushingdebris form a biopsy instrument which includes an outer piercing needlehaving a laterally positioned tissue receiving port which-opens into atissue receiving chamber and an inner cutting cannula having an axiallumen and a sharpened distal end, which is disposed coaxially andslidably within the outer piercing needle. Further included in thebiopsy instrument is a vacuum lumen disposed beneath the tissuereceiving port which further comprises at least one fluid communicationport disposed distally of the distal end of the inner cannula when theinner cannula is in its fully advanced position. The inventive methodincludes the steps of advancing the inner cannula of the instrument sothat it extends distally sufficiently to completely close off the tissuereceiving port and then injecting a pressurized fluid through one of theinner cannula and the vacuum lumens, so that the fluid flows through thefluid communication port and into the other one of the two lumens, fromwhich the fluid returns to its source, thereby flushing accumulateddebris from the biopsy instrument.

The invention, together with additional features and advantages thereofmay best be understood by reference to the following description takenin conjunction with the accompanying illustrative drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of an automatic core biopsy device of thetype shown and described in co-pending patent application Ser. No.08/1217,246;

FIG. 2 is a schematic plan view, from the left side, of a portion of theneedle assembly of the device illustrated in FIG. 1, showing the devicebefore it penetrates a target lesion;

FIG. 3 is a schematic plan view similar to FIG. 2, showing the deviceafter it has penetrated the target lesion, in a position to begincollecting tissue samples;

FIG. 4 is a cross-sectional view, from the left side, of the needleassembly of the device illustrated in FIG. 1;

FIG. 5 is an enlarged perspective view of the portion of FIG. Idelineated by the numeral 5.

FIG. 6 is a cross-sectional view of one embodiment of the needleassembly illustrated in FIG. 5;

FIG. 7 is a cross-sectional view taken along lines 7-7 of FIG. 6;

FIG. 8 is an enlarged cross-sectional view taken along lines 8-8 of FIG.3;

FIG. 9 is an enlarged cross-sectional view similar to FIG. 8,illustrating the withdrawal of the cutter after insertion of the needleinto the target lesion;

FIG. 10 is an enlarged cross-sectional view similar to FIG. 8,illustrating the prolapse of tissue into the tissue receiving portfollowing the application of the vacuum pressure;

FIG. 11 is an enlarged cross-sectional view similar to FIG. 8,illustrating the simultaneous rotation and distal advancement of thecutter to cut off a tissue sample;

FIG. 12 is an enlarged cross-sectional view similar to FIG. 8,illustrating the proximal withdrawal of the cutter with the tissuesample contained therein;

FIG. 13 is an enlarged cross-sectional view of the interface between theproximal end of the tissue cassette and the tissue cassette housingillustrated in FIG. 4, showing the operation of the knock-out pin toretain the tissue sample in the tissue cassette as the cutter iswithdrawn proximally;

FIG. 14 is a cross-sectional view taken along lines 1414 of FIG. 10;

FIG. 15 is a cross-sectional view taken along lines 15-15 of FIG. 12;

FIG. 16 is a cross-sectional view similar to FIG. 14, wherein the outerneedle and inner cutter have been rotated approximately 90 degreescounterclockwise to take a second tissue sample;

FIG. 17 is a cross-sectional view similar to FIG. 15, wherein the outerneedle and inner cutter have been rotated approximately 300 degreescounterclockwise, and a fourth tissue sample has bee taken

FIG. 18 is a cross-sectional view of a second embodiment of the needleassembly shown in FIG. 3;

FIG. 19 is a cross-sectional view along lines 19-19 of FIG. 18;

FIG. 20 is a cross-sectional view of a third embodiment of the needleassembly shown in FIG. 3;

FIG. 21 is a top plan schematic view of the tissue receiving port of afourth modified needle assembly embodiment;

FIG. 22 is a cross-sectional view similar to FIG. 3, illustrating afifth modified needle assembly embodiment;

FIG. 23 is a cross-sectional view through the tissue port of a needleassembly Like that shown in FIG. 5, illustrating a potential tissuebinding situation under certain operating regimes;

FIG. 24 is a fragmentary cross-sectional view of the cutter portion of asixth modified needle assembly embodiment, illustrating an inventivesolution to prevent potential tissue binding situations like thatillustrated in FIG. 23;

FIG. 25 is a cross-sectional view of a prior art single-use biopsydevice, of the type shown and described in U.S. Pat. No. 4,699,154;

FIG. 26 is a fragmentary cross-sectional view of a modified needleassembly for a biopsy gun of the type illustrated in FIG. 25,illustrating the needle assembly in a first position for advancing theneedle assembly through tissue to a selected tissue sample site;

FIG. 27 is a fragmentary cross-sectional view of the needle assemblyillustrated in FIG. 26, showing the needle assembly in a second positionfor obtaining and cutting a tissue sample;

FIG. 28 is a fragmentary cross-sectional view of the needle assemblyillustrated in FIG. 26, showing the needle assembly in a third positionwherein the tissue sample has been severed and is contained in thetissue receiving port of the needle assembly;

FIG. 29 is a fragmentary cross-sectional view of a second modifiedneedle assembly for a biopsy gun of the type illustrated in FIG. 25,illustrating the needle assembly in a first position for advancementinto the selected tissue sample site;

FIG. 30 is a fragmentary cross-sectional view of the needle assemblyillustrated in FIG. 29, showing the needle assembly in a second positionafter capture of a tissue sample;

FIG. 31 is a schematic exploded view of a third modified needle assemblyfor a biopsy gun of the type illustrated in FIG. 25;

FIG. 32 is a schematic side elevational view of the needle assemblyillustrated in FIG. 31, showing the assembly in a first positionapproaching a selected tissue sample;

FIG. 33 is a schematic side elevational view similar to FIG. 32,illustrating the needle assembly in a second position grabbing theselected tissue sample; and

FIG. 34 is a schematic side elevational view similar to FIG. 32,illustrating the needle assembly in a third position after capture ofthe selected tissue sample.

DESCRIPTION OF THE INVENTION

Referring now to FIGS. 1, 4, and 5, a preferred embodiment of anautomatic core biopsy device 10 of the type disclosed in related patentapplication Ser. No. 08/217,246 is illustrated The illustrated biopsyinstrument 10 comprises a housing 14 having a hinged lid 16. A needleassembly 18 extends out of the housing 14, and comprises a hollow outerpiercing needle 20, an inner cutter 22 having a lumen 23 (FIG. 5), atissue cassette housing 24, and a tissue cassette 26. The hollow outerpiercing needle 20 further includes a tissue receiving port or bowl 28.A thumbwheel 30 interconnects the tissue cassette housing 24 and thehollow outer piercing needle 20, preferably permitting rotation of theneedle 20 without rotating the tissue cassette housing 24, as will bemore completely described hereinbelow. A vacuum port 32 in the tissuecassette housing 24 is adapted for attachment to a vacuum source througha tube or tubing 34, in order to provide a vacuum at the tissuereceiving port or bowl 28. Preferably, the vacuum is supplied through aseparate vacuum lumen 35, but may alternatively or simultaneously besupplied directly through the lumens of the hollow outer piercing needle20 and the inner cutter 22, respectively, if desired

Telescopically and coaxially arranged within the hollow outer piercingneedle 20 and the inner cutter 22 is a knock-out-pin 36. It is mountedto be stationary, and is preferably fabricated of stainless steel, butmay also be constructed of other biocompatible materials, such asplastic. The pin 36 preferably is tubular, and the hub H of theknock-out pin serves as a secondary vacuum port which supplies thevacuum through the needle 20 and inner cutter 22. Surprisingly,Applicants have found that it is important to appropriately size theknock-out pin to minimize clogging problems. For this reason, it hasbeen found tat,t for the preferred embodiment where the inner diameterof the outer piercing needle 20 is approximately 0.074 inches and theinner diameter of the inner cutter 22 is approximately 0.063 inches, theeffective diameter of the knockout tube 36, meaning the cross-sectionalarea of the tube, should be at least approximately 0.030 inches.Preferably, the effective diameter of the knock-out tube is about 0.045inches.

The biopsy instrument housing 14 contains the driving mechanisms andcontrols for operating the needle assembly 18, and may be mounted in astationary fashion on a base 37. This base 37 may be an integral part ofthe housing 14 and is preferably designed to mate with an I-beam rail ofa stereotactic imaging unit, but ray be modified and designed to matchand mate with any of the various imaging units available in theindustry. The driving mechanisms for the illustrated preferredembodiment include a long spur gear 38 and a cutter drive gear 40, whichis housed within a pinion housing 42 and is rotatably and drivinglyattached to the inner cutter 22 within the housing 14. In order torotate or oscillate the cutter 22, the gear 38 is rotated by a drivingmotor or stepper motor (not shown). Rotation or oscillation of the gear38 in turn drives the gear 40 to rotate or oscillate, thereby rotatingor oscillating the cutter 22.

In addition to rotation or oscillation, the cutter 22 may also be drivento travel axially, both distally and proximally. A slide handle 44,which is attached along with the pinion housing 42 to a slide (notshown), may be actuated by an operator in either direction, asillustrated by the arrow 46, to drive the pinion housing 42 axially.Since the cutter 22 is fixedly attached to the pinion gear 40, which inturn is contained within the pinion housing 42, the cutter follows theaxial travel of the pinion, housing, permitting the operator to advanceor retract the cutter, as desired

A piercing mechanism or linear actuator 47, located distally of apartition 48 in the housing 14, functions to rapidly advance the entireneedle assembly 18 distally in order to locate the tip of the outerpiercing needle 20 at the site from which one or more tissue samples aredesired. The piercing mechanism preferably includes a driving spring(not shown), a carriage assembly 50, which is attached to a proximal endportion 52 of the tissue cassette housing 24, a cocking lever 54 whichoperates against a fixed lever 55, a pierce button 56, and a safetybutton 57. Operation of the piercing mechanism is described in greaterdetail hereinbelow.

Of course, the illustrated embodiment is just one of many possible waysto drive and control an automatic core biopsy device of the type shownand described. For example, the control system could be an integral partof the computer system in the stereotactic or other imaging device usedto guide the biopsy device, so that the stereotactic device computerwould be used to control the cutter, the angular and longitudinalposition of the piercing needle 20, and the knock-out tube position.Additionally, different driving mechanisms could be employed, such assubstituting a friction drive for the long spur gear drive. In someinstances it may be preferred to be able to rotatably and linearly driveand -control the hollow outer piercing needle and the knockout pin, aswell as the inner cutter, as disclosed in co-pending application Ser.No. 08/217,246, or to employ one of the other needle assembly or needleassembly driving arrangement embodiments -disclosed therein. Of course,any of the embodiments disclosed in that application may also be used inconjunction with the inventions herein disclosed

In operation, as described in the aforementioned co-pending applicationand with particular reference to FIGS. 2, 3, and 8 through 13, inaddition to FIGS. 1, 4, and 5, the point 58 of the needle 20 is firstmoved into position to pierce the lesion or selected tissue which is tobe sampled Rigs. 2 and 3). The initial global position of the point 58with respect to the tissue area being sampled is determined by theoverall position of the biopsy instrument 10 with respect to thepatient. For example, the biopsy instrument 10 may be mounted on acommercially available stereotactic guidance system (not shown),commonly used in the medical field for accurate positioning of a varietyof medical devices with respect to a patient and with respect to alesion within a patient. A detailed description of such a motorizedbiopsy needle positioner, i.e. a stereotactic guidance system, is givenin U.S. Pat. No. 5,240,011, issued on Aug. 31, 1993, to Michael Assa,which is hereby incorporated herein by reference. The suspect lesion 59within the tissue to be sampled is targeted according to theinstructions provided with the stereotactic guidance system. Thestereotactic guidance system will enable an operator to advance thepoint 58 until it is adjacent the specific lesion region 59 to besampled, as illustrated in FIG. 2.

Once the point 58 is adjacent to the specific lesion region to besampled, fine tuning of the location of the point 59 within the tissuesample is preferably accomplished by actuating the linear actuator 47 tothereby advance and retract the hollow outer piercing needle 20 alongits axis (the actuator 47 may, however, be used for rapid piercing aswell). While the linear actuator 47 illustrated in FIG. 1, which uses apotential energy device (spring), is preferred, any of a variety ofdevices capable of inducing linear motion may be employed, includingsolenoids, pneumatic cylinders, or potential energy devices such assprings, motors, or the like. In operation of the preferred embodiment,the cocking lever 54 is pulled proximally against the fixed lever 55 tocompress the spring and cock the carriage assembly 50 in its proximalposition, as shown in FIG. 2. Then, when the needle 20 is positionedoutside the lesion, as illustrated in FIG. 2, the pierce button 56 isdepressed, releasing the carriage housing 50 so that the spring uncoils,forcing it rapidly in the direction of the arrow A (FIG. 3), such thatthe point 58 of the needle pierces the lesion 59. Alternatively, thisprocedure could be automated, using a needle control unit to sendsignals to the linear actuator, which, in turn, would advance andretract the hollow outer piercing needle 20 along its axis.

Now with particular reference to FIGS. 8-13, as seen in FIG., 8, theneedle 20 is preferably advanced into the lesion 59 with the innercutter 22 in its fully advanced position to close off the tissuereceiving port 28, thus preventing snagging and tearing of the tissueduring slow linear movement of the needle 20. After the hollow outerpiercing needle 20 has been positioned at the precise location withinthe lesion 59 at which it is desired to obtain a tissue sample, a vacuumsource is actuated to apply a vacuum to the vacuum connection 32 in thetissue cassette housing 24 through the vacuum tube 34 (FIG. I) as thecutter is retracted proximally (FIGS. 9 and 10). As a result, a regionof low pressure is generated within the hollow outer piercing needle 20in the vicinity of the tissue receiving port 28, and through the vacuumlumen 35. This facilitates the prolapse of tissue immediately adjacentto the tissue receiving port 28 into the interior of the hollow outerpiercing needle 20.

Once the tissue is fully prolapsed into the tissue receiving port, asshown in FIG. 10, the prolapsed tissue sample 60 is severed from themain tissue mass by the advancement of the cannular inner cutter 22(FIG. 11). The advancement of the inner cutter 22 is achieved byadvancing the slide knob 44 attached to the pinion housing 42, thusadvancing the inner cutter 22 along its axis within the hollow outerpiercing needle 20 past the tissue receiving port 28, to thereby severthe prolapsed tissue sample from the rain tissue mass. After beingsevered from the tissue mass, the tissue sample is packed into the innercutter as it moves forward against the needle pin 61 and rests insidethe inner cutter 22. The inner cutter 22, containing the tissue sample60, is then withdrawn by reacting the slide knob 44 (FIG. 12). Thetissue sample is held in the inner cutter 22 as it is withdrawnproximally toward the tissue cassette housing 24 by friction with theinner walls of the cannula. Suction created by the vacuum source canalso be used to retain the sample.

As the inner cutter 22 is withdrawn through the tissue cassette housing24, the tissue sample 60 is deposited into the tissue cassette 26 bymeans of the tubular knock-out pin 36, the distal end of which stops thetissue sample within one of the tissue containment chambers 62 (FIG. 1),as is more fully described in the related application Ser. No.08/217,246. Once the tissue cassette 26 is filled with tissue samples,it may be removed from the tissue cassette housing 24 and transported toa laboratory for analysis, without the necessity of handling thesamples. If additional samples are desired, a new tissue cassette 26 maybe immediately inserted into the tissue cassette housing 24 and thecollection of samples may continue.

Referring now to FIG. 4, the needle assembly 18 of FIG. 1 is illustratedin greater-detail. Significantly, the preferred embodiment of the needleassembly comprises a two-piece body, including the hollow outer piercingneedle 20, with its inner cutter 22 and knock-out pin 36, and the tissuecassette housing 24. The frame of the tissue cassette housing 24(excluding the cassette 26) is preferably molded from a single piece ofplastic. If clear plastic is used, an additional advantage is theresultant ability to view the collected tissue specimens in thecassette, which is located in a cassette port P in the housing 24 duringoperation of the device. Magnification of the specimen is obtained bymolding the top surface of the housing 24 to be convex, while the innersurface is substantially flat. The preferred one-piece plastic cassettehousing 24 includes a shaft portion 63, which provides a conduit forholding the cutter 22 and the knockout pin 36, and the proximal endportion 52, which in turn is adapted to be mounted on a post 64 withinthe housing 14 (FIG. 1), forming a part of the carriage assembly 50.This portion of the cassette housing thus provides the support for theentire cantilevered needle assembly 18.

Yet another advantageous feature of the preferred needle assembly 18 isthe thumbwheel 30. The needle 20 is glued or otherwise securely attachedto the thumbwheel, which is then snapped into the housing 24. O-rings 65fluidly seal the interface between the housing 24 and the thumbwheel 30,in order to preserve the vacuum between the port 32 and the vacuum lumen35 while simultaneously permitting rotation of the thumbwheel relativeto the fixed housing 24. Because of this inventive feature, the vacuumray be communicated to the needle 20 from the vacuum port 32 in thehousing 24 no matter what the orientation of the needle is, without theproblem sometimes encountered in prior embodiments wherein the vacuumtube 34 wraps about the housing 24 as it rotates with the needle 20. Theability to keep the cassette housing 24 stationary solves this hose wrapproblem.

FIGS. 14-17 illustrate a procedure enabled by the thumbwheel 30, wherebyfour tissue samples 60 may be acquired from four different angularpositions and deposited in the sample cassette 26 without removing thehollow outer piercing needle 20 and the tissue receiving port 28 fromthe lesion 59. Furthermore, the integrity of each sample may bepreserved and a record of the location from which of the four samples isacquired may be created by storing the samples in individual samplecontainment chambers 62 (FIG. 1). FIG. 14 is a cross-sectional viewalong lines 14-14 of FIG. 10, which illustrates preparations for thetaking of a first sample 60 (FIG. 11) with the needle 20 and associatedvain lumen 35 angularly oriented so that the tissue receiving port is inan upright position within the lesion 59. FIG. 15 is a cross-sectionalview along lines 15-15 of FIG. 12, wherein the needle 20 is angularlyoriented in the same position as in FIG. 14, after the tissue sample hasbeen removed. The void 66 represents the location from which the samplewas taken. FIG. 16 shows the needle assembly as illustrated in FIGS. 14and 15, but where the thumbwheel 30 (FIG. 4) has been used to rotate theneedle 20 approximately 90 degrees counterclockwise. A second sample isto be taken from his angular location.

Finally, FIG. 17 is yet another similar view, wherein the needle 20 hasbeen rotated by the thumbwheel 30 approximately 300 degreescounterclockwise from the original orientation shown in FIGS. 14 and 15(it should, however, be noted that the invention permits samples to betaken from any angular orientation between 0 and 360 degrees). A samplehas already been taken from this orientation, as well as from the 180degree orientation, so that the void 66 now extends entirely about theneedle assembly and four tissue samples have been removed.

Now with reference to FIGS. 18 and 19, a modified embodiment of aportion of the needle assembly 18 of FIGS. 1, 4, and 5 is illustrated,wherein like elements are designated with like reference numerals,followed by the letter a This needle assembly embodiment may be used inconjunction with a vacuum which is drawn through the cutter lumen 23 a,and particularly in a procedure where the physician wishes to obtainonly a single sample and wants to retain the tissue sample in the tissuereceiving port 28 a for retrieval (i.e. a “single-core” procedure).

Attached to the proximal end of the needle point 58 a is a distal tip 66of a tissue stop or wire assembly 67, which comprises a wire 68 which isintegral with and extends proximally of the tip 66. The attachment ofthe point 58 a to the tip 66 is preferably made by brazing, though otherequivalent known attachment methods may be used as well. The wire 68extends beneath the entire axial length of the tissue receiving port 28a. Proximally of the tissue receiving port 28 a, and near the proximalend of the wire 68, is a corkscrew portion 69, which has a diameter orcross-sectional width just slightly less than the internal diameter ofthe inner cutter 22 a, as illustrated in FIG. 19.

In operation, with the cutter 22 a withdrawn proximally from the regionof the tissue receiving port 28 a, the wire assembly 67 is stationary inthe lumen of the hollow outer piercing needle 20 a With the needle inposition in the tissue to be sampled, a vacuum is drawn through thecutter lumen 23 a and the needle lumen, thereby prolapsing tissue intothe tissue receiving bowl 28 a. A potential problem is that such tissuewill prolapse all the way to the bottom of the bowl at a proximal regionof the bowl, thereby cutting off the vacuum distally of the blockingportion. Without the vacuum, the distal portion of the bowl may notreceive a full volume of prolapsed tissue, thereby causing the tissuesample, when cut, to be only a partial sample. However, the wire 68functions to hold the prolapsed tissue in an elevated position above thebottom of the bowl, thereby preventing blockage of the lumen. Thispermits the vacuum to be transmitted all the way to the tip 66 so that afull-volume sample is assured.

Once the prolapsed tissue sample has been received, and cut off by theinner cutter 22 a, the corkscrew portion 69 functions to prevent thesample from being sucked or pulled out of the bowl 28 a duringwithdrawal of the cutter. Then, after the needle is withdrawn from thepatient's body and the cutter 22 a is withdrawn from the bowl 28 a, thetissue sample remains in the bowl and may be retrieved directly from thebowl by the physician or an assistant.

In one preferred embodiment, the inner diameter of the hollow outerpiercing needle 20 a was 0.074 inches, and the inner diameter of theinner cutter 22 a was 0.063 inches. The diameter of the wire 68 was0.014 inches, and the diameter or cross-sectional width of the corkscrewportion 69 was 0.060 inches. Of course, many other dimensions may beutilized as well. Additionally, while a corkscrew configuration ispreferred, many other configurations may be employed, as long as theyfunction to prevent proximal migration of the tissue sample, especiallyduring withdrawal of the cutter. For example, a simple kink in the wiremay be used, instead.

Now with particular reference to FIGS. 5 and 6, the distal portion ofthe needle assembly illustrated in FIGS. I and 4 is shown in perspectiveand in cross-section, respectively. Two particular features notpreviously discussed are of note. First, in this particular embodiment,two preferably round vacuum ports 70 communicate between the tissuereceiving port 28 and the vacuum lumen 35. The distal port 70 is locateddistally of the tissue receiving port opening, so that it lies justproximally of the point 58 and beneath overhang portion 71 of the needle20. In the preferred embodiment, it has a diameter of approximately0.042 inches. The proximal port 70, on the other hand is significantlysmaller, preferably about one-half the diameter of the larger port(approximately 0.020 inches), and lies directly beneath the tissuereceiving port 28.

The second feature of note is related to how the needle point is groundfor sharpening, As illustrated in FIG. 5, it is preferred that the pointbe ground to form a plurality of facets 72 (preferably three) wherein notwo facets axially intersect within the circumferential arc defined bythe tissue receiving port 28. Thus, the needle point 58 defines arelatively flat surface on its upper side, as illustrated This isadvantageous in tat the flat top surface 72 lifts the tissue upwardlyand thereby assists its entry into the tissue receiving port 28. On theother hand, if two of the facets 72 axially intersect within the arcdefined by the tissue receiving port, the tissue often tends to split,potentially degrading the sample quality.

Referring now to FIG. 20, a modified embodiment of the needle assembly18 illustrated in FIG. 6 is shown, herein like elements are designatedby like reference numerals, followed by the letter b. The primarydifference between his embodiment and that of FIG. 6 is the employmentof a greater number of vacuum ports 70 b, preferably eight, between thevacuum lumen 35 b and the tissue receiving port 28 b. In thisembodiment, preferably each of the ports 70 b is round and has adiameter of approximately 0.042 inches. Also, in this embodiment all ofthe ports are located beneath the opening of the tissue receiving port,as illustrated None lie beneath the overhang portion 71 b.

The reason for the two different vacuum port configurations in FIGS. 6and 20 is that each has advantages over the other when sampling certaintypes of tissue. For example, in relatively fatty tissue, the eight holeembodiment illustrated in FIG. 20 may have a greater tendency to clog.Clogging sometimes occurs when numerous samples are being taken because,as tissue is received into the tissue receiving port, the vacuum drawnthrough the vacuum ports 70 b tends to draw tissue past the ports andinto the vacuum lumen 35 b. Then, when the cutter 22 b advances to severthe tissue sample, small pieces of tissue within the vacuum ports fallinto the vacuum lumen 35 b. Over many sampling cycles, the tissuebuildup in the vacuum lumen 35 b partially blocks the vacuum to thedistal ports, causing an uneven and diminished overall vacuum pressureand thereby reducing the quality of the tissue samples being obtained.The two-port embodiment illustrated in FIG. 6 avoids this problem,because the single small port subject to contact with the tissue sampleprolapsing into the tissue receiving port is so small that even iftissue does fall into the vacuum lumen from this port, it does not buildinto a mass sufficient to cause a blockage. The distal port, on theother hand, is protected by the overhang 71 from contact with thetissue, so no tissue can become caught in the port to create clogging,

When relatively hard tissue is being sampled, in contrast, theeight-port embodiment shown in FIG. 20 may be preferable. This isbecause hard tissue is less pliable, and therefore generally requires amore evenly distributed vacuum pressure to draw it fully into the tissuereceiving port Obviously, the higher number of evenly spaced ports inthe FIG. 20 embodiment will provide this necessary drawing pressure .Furthermore, hard tissue is much less likely to actually be drawn intothe vacuum ports 70 b, so clogging is not a likely issue.

FIG. 21 illustrates a further modified embodiment of the needle assembly18 illustrated in FIG. 6, wherein like elements are designated by likereference numerals, followed by the letter c. The difference between theFIGS. 6, 20, and 21 embodiments is at in FIG. 21, the vacuum ports 70 care arranged at an angle α with respect to the tranverse axis 80 of theneedle assembly 18 c. Additionally, the side walls 82 of the tissuereceiving port 28 c are preferably arranged at substantially the sameangle α. In the preferred embodiment, the angle α is approximately 15-75degrees. This angled orientation is advantageous because it permits thecutter 22 c (not shown in FIG. 21) to traverse the vacuum ports 70 c andside walls 82 of the tissue receiving port 28 c more easily and minisdamage to the cutter blade due to interfering contact with these edges.

Yet another modified embodiment of the needle assembly embodimentillustrated in FIG. 6 is shown in FIG. 22. In this embodiment, likeelements are designated by like reference numerals, followed by theletter d.

The FIG. 22 embodiment is designed to assist in solving the cloggingproblem discussed with respect to the FIGS. 6 and 20 embodiments andsometimes encountered during the process of collecting a number oftissue samples from a patient during a single procedure. As previouslydiscussed, the problem is that bits of tissue, blood, and otherbiological debris will, over time, become detached from the tissuesamples being collected and become lodged in the tissue receiving port28 d, vacuum ports 70 d, or in one of the lumens 23 d or 35 d. Since thevacuum ports 70 d are relatively small, the problem of clogging thoseports is most acute, as the resultant reduced vacuum in the tissuereceiving port 28 d may cause the collection of partial tissue samples.Consequently, as illustrated in FIG. 22, a flush port 84 may be locatedbetween the vacuum lumen 35 d and the piercing needle lumen, similar tovacuum ports 70 d bit located distally of the closed (most advanced)position of the cutter 22 d. Then, when the cutter 22 d is in the closedposition, as illustrated, a pressured saline solution may be permittedto flow through the cutter lumen 23 d into the needle lumen distally ofthe cutter, then through the flush port 84 as shown by the arrow 86, andfinally returned to its source through the vacuum lumen 35 d. Thisprocedure clears any accumulated debris and thus helps to ensure hat thetissue samples are as complete as possible. A safety feature preventssaline from being injected through the system when the cutter is not ina fully closed position; i.e. completely blocking the tissue receivingport 28 d.

As illustrated in FIG. 23, a problem sometimes encountered duringoperation of the biopsy device 10 (FIG. 1) is that the tissue sample 60being pulled into the tissue receiving port or bowl 28 may have atendency to bind as the relatively large cross-section of tissue isnecked down into the space between the rotating cutter 22 and the needle20. This problem is worsened because of the possible rotation of thecutter 22 relative to the stationary needle 20. In FIG. 24, a solutionto this problem is illustrated, wherein the cutter 22 e is modified tocomprise a relatively short blade portion 90, and a non-rotating sleeve92, preferably comprising a polyamide or a similar low-friction materialor coating, surrounds the remainder of the cutter and translates axiallywith it The sleeve thus acts as an anti-tissue wrapping bearing, therebyhelping to prevent tissue binding, and as a bearing to the cutter.

FIG. 25 illustrates a known prior art single-use biopsy device asdisclosed in U.S. Pat. No. 4,699,154 and Re. 34,056, both previouslyincorporated herein by reference. It should be noted hat this embodimentis merely representative of many different types of such devicescurrently or potentially available, any of which would be suitably usedin conjunction with the inventive embodiments. However, the illustratedembodiment is illustrative and will serve as a good point of reference.

In the device 94, a needle assembly 96 comprises a hollow outer cuttingcannula or needle 98 and an inner piercing needle 100. The needles 98and 100 are pointed at their distal end, and the inner needle 100 isalso provided with a tissue receiving notch 102 at its distal end forreceiving the tissue sample. At their proximal ends, the needles 98 and100 are provided with heads 104 and 106, respectively, for mountingwithin the housing 108 of the sampling device. A front slide 110 and arear slide 112 are slidably provided along the axial direction of thehousing 108. Each slide 110 and 112, respectively, is actuated by atleast one spring 114 and 116, respectively, biasing the respective slidein a distal direction. The spring 114 acts between a stop 118 providedon the slide 110 and a fixed transverse wall (not shown) in the housing108. The spring 116 acts between a stop on the slide 112 and the rearend wall 120 of the housing 108. In the housing 108, there are twoparallel slide bars or guide rods 122, 124 on which the slides 110, 112run.

The front slide 110 may be retained in a proximally withdrawn positionby means of a hook provided on a tongue member 126 protruding from theslide, the tongue member engaging the bottom edge of the aforementionedtransverse wall (not shown). The rear slide 112 may in a correspondingway be hooked and retained in a withdrawn position by means of a hook128 protruding from the slide, which in turn engages a springy hookmember 130 at the rear wall 120 of the housing

The tissue sampling device 94 is loaded and released in the followingmanner. In the unloaded initial position, the slides 110, 112 are eachbiased distally (toward the left) by the springs 114, 116, respectively.To load the device, the needle assembly 96, in which the inner needle100 is freely slidable in the hollow outer cannula 98, is movedproximally (to the right) and placed in the correct position in thehousing 108, so that the needle heads are engaged into the slides 110,112, which are configured to receive them, such that each needle head104, 106 follows the movements of the slides 110, 112, respectively.

Thus, when the needle assembly 96 has been placed in the device, thedevice is energized in that the slides. 110, 112 are movedsimultaneously to their latched positions, whereby the springs 114, 116are compressed and would act to return the slides 110, 112 to theirinitial position if released from the latching hooks 126, 128, and 130.

When the needle assembly 96 has been positioned at the desired tissuelocation, the sampling is carried out by pressing a release button 132,whereby the engagement between the hooks 128 and 130 is interrupted.Because of the biased spring 116, the slide 112 together with the innerneedle 100 is thus pushed distally toward the left to its initialposition. For a short period of time, the slide 110, together with theouter cannula 98, is still retained in its energized position Thus, theinner piercing needle 100 protrudes from the outer cannula 98, therebyexposing the notch 102. Immediately after having reached its initialposition, however, the slide 112 impacts and abuts the hook spring(tongue member) 126, and interrupts the engagement of the hook with thetransverse wall (not shown), whereby the spring 114 also pushes back theslide 110 distally to its initial position. Consequently, the outercannula 98 again is pushed over the side facing notch 102 in the innerneedle 100, thereby severing the tissue sample that has prolapsed intothe notch Thereafter the needle assembly 96 is withdrawn from the tissueand removed from the sampling device, following which the sample isanalyzed.

While such a device works fairly well for its intended purposes, asdiscussed in the Background of the Invention, there are a number ofproblems inherent in their operation. Most significantly, there is nopositive means for engaging the tissue sample within the notch 102,particularly since no source of vacuum is available, as in theembodiments of FIGS. 1-24, to assist in collection of the tissue.Consequently, several inventive embodiments including mechanicalelements for capturing the tissue are disclosed herein, each of whichdramatically improve the quality and quantity of the tissue samplescollected, on a consistent basis.

Referring now to FIGS. 26-28, a modified embodiment of the needleassembly 96 of FIG. 25 is illustrated, wherein like elements aredesignated by like reference numerals, followed by an a In thisembodiment, in their initial position, as shown in FIG. 26, with bothsprings energized the inner needle 100 a is retracted within the outercannula 98 a, and cutter leaflets 134 are in a closed position on thedistal end of the needle 98 a. Preferably, there are two, four, or sixcutter leaflets 134, which in the closed position come together to forma piercing cone. Of course, however, any number of leaflets may beemployed within the scope of the invention.

FIG. 27 illustrates the intermediate position immediately after therelease button 132 (FIG. 25) has been activated. At this juncture, thespring 116 propels the inner needle 100 a distally, forcing the leaflets134 open. The sharpened distal edges 136 of the needle 100 a begin tocut tissue, which is contained within the distal end portion of theneedle 100 a. Ten, upon release of the spring 114, the outer cannula 98a is propelled distally, as shown in FIG. 28, causing the leaflets 134to snap closed to sever and contain the tissue sample 138.

It should be noted that this embodiment, while useful as a modificationto the FIG. 25 device, may also be employed in the FIG. 1 device. Inthis instance, the inner needle 100 a comprises a rotating cutter, whichtranslates back and forth as previously described.

FIGS. 29 and 30 illustrate a second modified embodiment of the needleassembly in the FIG. 25 device. Again, like elements are designated bylike reference numerals, followed by a b. In this embodiment, the innerneedle 100 b has been modified to include an “alligator” tip 140, whichincludes jaws 142, 144 and teeth 146. When the spring 116 is released,the inner needle 100 b shoots distally and captures tissue in theopening 148 within the jaws 142, 144. Then, when the spring 114 isreleased, the outer cannula 98 b shoots distally, severing tissue alongthe sides of the tissue sample opening 148 as it moves distally, andalso forcing the jaws 142, 144 shut, so that they “bite off” the end ofthe tissue sample 138 b, as illustrated in FIG. 30. This embodiment alsomay be adapted for use with the device of FIG. 1, if desired

Finally, FIGS. 31-34 illustrate a third modified embodiment of theneedle assembly in the FIG. 25 device. In this embodiment, like elementsare designated by like reference numerals, followed by a c. Like theFIG. 29 embodiment, the inner needle or “grabber” 100 c has beenmodified, this time to include a plurality of hooked extractors 150extending from its distal end. The outer cannula 98 c includes asharpened cutter point 152. In operation initially the grabber 100 c isretracted into the cutter 98 c while the device is in its energizedstate, the point 152 being used to pierce the body wall 154 as thedevice is guided to the desired tissue sample 138 c (FIG. 32). Then, asillustrated in FIG. 33, the grabber 100 c is shot distally by means ofthe release of spring 116. As it travels distally, the hooked extractors150 become extended and latch onto the tissue sample 138 c. Then, oncethe second spring 114 is released, the cutter 98 c shoots distally,collapsing the hooked extractors 150 and severing the tissue sample,which is received into the lumen of the cutter 98 c.

This embodiment, as well, may be adapted for use with the deviceillustrated in FIG. 1. Furthermore, while four extractors 150 are shown,in actuality any desired number may be employed, as long as they may befully retracted within the cutter 98 c.

While this invention has been described with respect to various specificexamples and embodiments, it is to be understood that the invention isnot limited thereto and that it can be variously practiced within thescope of the following claims.

1-26. (canceled)
 27. A biopsy device comprising: an outer hollow cannulahaving a closed tissue piercing distal tip and a lateral tissuereceiving port disposed proximally of the distal tip; a hollow innercutting member having a sharpened distal end for severing tissuereceived in the lateral tissue receiving port of the outer hollowcannula; and a rotatably driven tissue sample holder disposed proximallyof the lateral tissue receiving port, wherein the rotatably driventissue sample holder is adapted to receive at least one tissue samplesevered by the hollow inner cutter.
 28. The biopsy device of claim 27wherein the rotatably driven tissue sample holder is adapted to receivemultiple tissue samples.
 29. The biopsy device of claim 28 wherein therotatably driven tissue sample holder comprises a plurality of tissuesample chambers.
 30. The biopsy device of claim 27 wherein rotatablydriven tissue sample holder is rotatably driven by a drive motor. 31.The biopsy device of claim 30 wherein the rotatably driven tissue sampleholder is belt driven by the drive motor.
 32. The biopsy device of claim27 wherein the rotatably driven tissue sample holder comprises a beltdriven rotary tissue cassette.